Scooby-Doo 3: Monster Mayhem! is a 2012 film and sequel to 2004's Scooby-Doo 2 and 2002's Scooby-Doo. The film, like the second one, was directed by Raja Gosnell, written by James Gunn and was produced by Charles Roven and Richard Suckle. The film is a direct sequel to the second film, happening a year and a half after it.

Voices

Protagonists

Antagonists

All of the monsters are, like Scooby Doo 2: Monsters Unleashed!, animated.

Jim Cummings - Phantom of Vasquez Castle (Ghost)

James Sie - Samurai Ghost

Jeff Bennett - Dryad, Troll

Geno Segers - Mamba Wamba

Selena Gomez - Lila

Raven Symone - Cat Creature

Tom McGrath - Mamba Zombie

Kiefer Sutherland - Ghost Clown

Doug Jones - Rambling Ghost

Matthew Lillard - 30 Foot Shaggy

Prologue

A year and a half after the events of Scooby-Doo 2: Monsters Unleashed, the gang returns to the Coolsville Criminology Museum for the Grand Re-Opening. When there, Scooby and Shaggy eat the whole buffet, Velma and Patrick will give a tour of the museum, and Daphne and Fred will answer some questions for the press. However, during this time there is a loud bongo drums and maracas, and then a wall bursts open, and an evil villain, who is dressed in all black, a Clone Trooper-like mask with spikes coming out the top and a cape with a huge E on it. He triumphently states:

“Mystery Inc.! How nice to see you again, hows it going? It know how it's going for you: badly”

—Evil Figure

and with that, he snaps his fingers and the Mamba Wamba costume starts moving, then the Mamba Zombie next to it, then the Lila statue next to it. The Mambas then throw smoke pellets everywhere, scattering everyone except Mystery Inc. and Patrick, who try and come up with a plan for this mess.

Villains

There are a total of 25 monsters Mystery Inc. encounters over the course of the movie. Monsters who's names are in green have a major role, while monsters who's names are in red have minor roles.